Shape has line symmetry when one halfof it is the mirror image of the other half.

Symmetry exists all around us and many people see it as being a thing of beauty.

3Line Symmetry

If a shape can be folded in half so that one half fits exactly on top of the other, then we say that the shape has got line symmetry.

The fold is called a line of symmetry.

This shape has got a vertical line of symmetry.

4Line Symmetry in the Alphabet

Which letters have got lines of symmetry?

ABCDEFGHIJKLMNOPQRSTUVWXYZ 5Lines of Symmetry all around us

Which of these road signs have got lines of symmetry?

6Is a butterfly symmetrical? 7Examples of line symmetry 8Animals that have Line Symmetry

Here are a few more great examples of mirror image in the animal kingdom.

9

This photograph shows 2 lines of symmetry. One vertical, the other along the waterline.

(Notice how the prayer towers, called minarets, are reflected in the water and side to side).

10Rotational Symmetry

When a shape is rotated about its centre, if it comes to rest in a position and looks exactly like the original, then it has rotational symmetry

A shape like an equilateral triangle would have an order of rotational symmetry of 3

11Rotational Symmetry

The general rule for a regular polygon (shapes such as pentagons, heptagons, octagons etc.) is, that the number of sides is the same as the number of lines of symmetry, which is also the same as therotational symmetry order.

Just as two-dimensional shapes can have a mirror line, so solid three-dimensional shapes can have a plane of symmetry.

The symmetry planes of an object are imaginary mirrors in which it can be reflected while appearing unchanged

18Plane Symmetry 19Plane Symmetry 20Plane Symmetry 21Tesselation

A collection of shapes that fit together to cover a surface without overlapping or leaving gaps

May also be referred to as tiling

They can be regular or irregular

a regular tessellation is made up of congruent regular polygons - triangles, squares or hexagons

22Tiling with regular polygon

The only regular polygons that can tile the plane are

Equilateral Triangle

Square

Hexagon

and no more!!

23Whats wrong with the other regular polygons??PentagonRegular heptagon and those with more sides 24Tesselation

Can be an irregular tesselation

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